I've been having issues with my Nexus 5 and previous nexus 4 whilst on three UK.
Basically Sometimes data will stall on the up arrow only. I drag down the control menu from the top and the icon is showing signal strength and a sporadic up arrow. It either resolves itself after 2-3 mins or I have to put airplane mode on and off.
It's happened in areas of lots of users (Stansted airport) and areas with not alot (where I live)
I also think the error doesn't occur with an ee sim in the nexus 4 as the wife hasn't moaned yet.
Anyone had anything similar or fixed this?